Desulphurizing apparatus



R; P. HEUER DEsULPHURIzING APPARATUS Filed Jm. 18, `1941 4 sheets-sheet3 Myl, 1943 Y 7 RLP, HEUER i 2,319,402`

DESULPHURIZING APPARATUS f Filed Jap. 18, 1941 `4 sheets-sheet 4 zo ya6.o Y do 10.0 /zo 14o Jaa ao m i g' nella., "Research `Aly-inventionrelates tovan apparatus for the reatmentof `pig iron andthe productionof l i 1 me, This applicationfisa continuation inpart fimyf cope'ndingAapplication Serial?` No.` 304,484, 5 "edQNovemberv, 15, 1939; for ap@` 1paratua and procesa; which fresulted in `Patent 042,290,961, issuedJuly.28, 1942; t `The" apparatus claimed herein nndsits treatstus'efulness iniconn'ecti farcoke blastlfurnacetoproduce pig ironhigherf f i. sulphurthan thatultimately deslred."andjpref.

` `erably `atfalovver costthannormal'. by operati nggmthei'blastwiurnace; rat a lowertemperature awjl lmaterialrcausing higher`sulphur in;` the barge. IItJ facilitates treatment `oilthe `molten` iigfl ironthus produced witha basic slag externalo` thelblast `furnacehearth,` toliremo' ef-the eX-jv i ess sulphur from the molten pigironaron `thus produced/ma! be usedfin thefform'of cast` iron `or as raw"materialforfmakinfg lanci'` course, capable ofi` useinde'sulpliuriaa-Yl 1",loiothex' metals.`

i Oneof `the purposes of my n videa refractory linedfdesulphrizingfladleYwhose xisof *symmetry isi* vertical tojcontain1xiioltenij heqmoltenironyandi to `provide apparatus to` f m *horizontal plane`,whi1edesirably valso producp ngi irelative movementbetween th lag'" aridQthe`A H i Y i A, i rotate" molten iron AorV basic desulphuriaing slag` 35ncontact withthe iron by an'impelleror preferblyfa pluralityotlmpelle'r's 4turningjon"a verical axis andfprefe'rably` in a"ladle\lvhs`e `axis t o symmetry is vertical. The impellerswili prefatants'lagin-a ladle havingfiteaxis ofgnsymmetry substantiall'yverticaland toproduce fromp ionwinthe iron to brin'glthe impurities ron into contactwiththe slag, A i 1 y `Aifurther purpose isto provide ;iv`.pp`ara`tnY to`1`a`.gita.te molten pig iron in-thepresence'of` asu-l mythemagneticaction and` separately to lcirculatethe l lagin a different direction.i' y @A further purpose is to provide apparatusto im was t i f i bath,`the'slag being oppositelyirotated( .i

n'wlth `:the operation` "flo H rid/,or withlessbasic slag and/or withlowgrade l5) 'I'hvnileo i p p i invention. The forms fshownhave` beenchosen from Ithe standpoints of ,A satisfactory operation t andvconvenientillustration ofg the principles in- Y. volved. 'All onthenguresarediagrammatic. inven ionistopro- 25 Y A p section ofavdesulphurizingvessel in accordance il'QIlHiflth abasicdesulphuri'zingslag'fioatlngpn p i i s 4 yfwfligure 1a is a partirotary`motion to the metaLdesirablyin 30 :further-I purpose `is to provide"apparatus tol` u herotary movement of the iron, a verticalin'o"` i5` pFigure 9 isja is a fragment showing;` a modiiied 9 form ofdam applied tothe structure of Figure 8. Figure. 11" is agfragmentary top planwview ofLyr'igureio. n, y i 1+ Figure 12 is a fragmentary central verticalpex'natant` slag in la. ladle by means ofelectro-` `5`0 g x Figure '.10

l whirl a pig iron bathrlby `horizontalrotaryrelec-n; romagneticstirring and tomaintainf a substan-v `55 Aof"VV molten l on; the

`Furtherv purposes zappear in theaspecincation andintheclaims.`

` The present application incorporates freier-1 ence myUnited Statespatents andipatentfapplication', `Patent. No. 2,110,0`66pgranted'Marchl. i 1938,` for Iron and steel desulphurization; PatentA i No.2,110,067, granted March1,19385i'orlron"` desulphurization; PatentNoi-2,177,716, granted A October` 31'.` 1939, -:for Desulphurlzingapparatus Patent No; 2,193,593, granted March 12, 1940, for Irondesulphurlzation; and Serial` No. 304,484,`

nled November, 1`5. V1939. resulting in lPatent No. 235161.11151,`granted July 28, 1942, forDesulphuriz-` ing: apparatusv and process.Reference should be therdisclosure ofthe process.

. 'In thedrawings no attempt hasl been madeto illustrate allotthepossible embodiments of the,

lliguxe` 1 fis ,a diagrammatic central vertical with the! present.:invention, vlith cooperating structure.` i .t i i fragment ofFigureishowing Vcovers?applie'dnoverfY theopenings@Y A 2ris.a"centralvertical section of one i form of stirring impeller in accordance withthe i invention.:` `l i v i i i l i i f AFigure 2li-shows adiiferentlength of impeller 'extension fromthatshown in Figure 2.' g

\ Figure31i`s a "sideelevation of a variantform` p w iofistlrringimpeller in accordance with the inveni tion; v Y i e t Y u fAFigure i` is aside elevationof affu'rtherV variant 4formof"stirringimpeller. i

rablyiturninthesame directionp 40 `Awfurtherpurpose is to provide`"apparatus to vFigure 5 iisasection of Figure "4 on'thefline otatemolten iron inthe presenceof `a"s`uper l-lf i f 'Figured isa-diagrammatic central vertical sec- -tionof ja' modifled-form-ofdesulphurizing vessel. i

- Figure 7 ris'a`.\s'e`ction of Figure on the `line i Figures is acentral vertical section of a further modification in the desulphurizingvessel.`

section of Flgure along the'line yters the desulphurizing vessel.

section showing a further modication in the dam of Figure 8.

Figure 13 is a central vertical section of a further modification in thedesulphurizing ves sel.

Figure 14 is a section of Figure li3 on the line Id-IL Figure 15 is aside elevation of a modif-led form of desulphurizing vessel with anelectrical. diagram of a polyphase inductor coil applied thereto, themagnetic core being sectioned away Ior convenience in illustrating thecoil.

Figure 16 is a section of Figure 15 on the lin'e I6-|6.-

Figure 17 is a diagrammatic top plan view of a variant form ofelectromagnetic':v stirring ladle.

Figure 18 is a fragmentary side elevation of Figure 17.

Figure 19 is a diagrammatic horizontal section of a modifieddesulphurizing vessel.

Figure 20 is a curve showing the rate of sulphur removal from pig ironunder special controlled conditions.

In 'thel drawings like numerals refer to like depth of metal of 60inches or more is to be expected. Thus for a depth of 60 inches, anelapsed time of 720 minutes or 12 hours would be required todesulphurize to the above extent. This time is too long for mostoperating conditions.

The rate of reaction can be speeded up appreciably by agitating themolten metal and/or the slag in order to produce relative motion betweenthe slag and the metal at their point of contact, the so-calledslag-metal interface. It is believed that the slow speed ofdesulphurization which is obtained in a `quiet bath is due to theresistance which the sulphur encounters in the regions closely adjoiningthe slag-metal interface whilst passing from the metal to the slag. Whencontact is first established'between the pig iron and the To takeadvantage of this accentuated desulphurizing action at highertemperature, I place the desulphurizing vessel in a position adjoiningthe blast furnace. In this manner I avoid any temperature loss such aswould occur if the mol- -ten iron from the blast furnace is rst placedin a transfer ladle and then transported to a desulphurizing vessellocated, for example, at the mixer in the steel making plant.

Contaminations caused by impurities containing silica are to be avoidedand this can be effected by passing thevmolten iron through a smalltea-pot ladle or similar device just before it en- In this Way thesiliceous impurities are separated and the desulphurizing slag is kepuniform with as high a ratio ofv lime to silica as intended.

Agitation of the desulphurizing slag and molten pig iron is necessary inorder to cause the desulphurizing reaction to proceed with convenientspeed. The present inventor has performed experiments without agitatingthe molten slag and molten pig iron. Figure 20 shows the rate of sulphurremoval under certain xed conditions, using a slag consistingof blastfur.-

v nace slag, 30% iluorspar and 30% burnt lime,

without agitation. In this gure the molten pig iron contained 0.07%sulphur atthe beginning of the experiment. This iron was treated withdesulphurizing slag of the composition just noted under deoxidizingconditions and freedom from air contamination, and samples of iron werewithdrawn for chemical analysis at specified times. In Figure 20 theexperimental data has been plotted in a curveshowing, as the ordinate,

slag, the slag rapidly absorbs sulphur but the reaction soon slows downbecause, without agitation', the system approaches equilibrium only inthe limited region which is not too far removed from the slag-metalinterface. By providing a relative motion between the mass of the slagand theiron, thereby bringing fresh slag and iron into the zone adjacentto the slagmetal interface, it ls possible to speed the removal of thesulphur. By continuing this process of relative motion the diillcultiesof slow speed operation as described above in quietibaths can beovercome. The present invention is concerned with agitation to producerelative motion between the slag and the metal in order to speed up thereaction and obtain a higher content of sulphur in the slag and/or alower content of sulphur in the iron than would otherwise be obtained.

Figure 1 illustrates a `desulphurizing vessel 20 equipped with amechanical agitating device for obtaining increased relative motionbetween the molten pig iron and the supernatant slag. Such a vesselmight contain from 40 to 200 tons or more of molten pig iron. The slaglayer might approximate 1% to 10% or more of the depth oi' the molteniron. The shape of the vessel is approximately circular or oval in crosssection and the axis of symmetry, that is, the axis runningperpendicular to the plane of circular or oval cross section, isvertical. 1

The vaxis of symmetry as referred to herein will be what is commonlyIcalled the major axis in the ordinary case. Where the ladle crosssection isl shell 2|r substantially gas tight and capable of.

protecting the contents-from access of the atmosphere or other oxidizinggases. The refractory lining 22 consists preferably of carbon ormagnesite bricks which have suitable resistance to the corrosive actionof the ladle contents. In order to conserve heat, these refractorybricks may be backed up with refractories 23 having lower thermalconductivity, as for example iireclay brick having an appreciably largerpercent of pore space than normal for such products. In some casesflreclay brick may also be used in direct contact with the contents ofthe ladle, as for example in the lower part where the slag does not comeinto contact with the fireclay refractories for long periods of time.

A roof or cover 24 is provided for the ladle. Flreclay or other suitablerefractories 25 such as carbon or magnesite can be used in lining thisroof. The roof can be supported by hangers or other suitable means (notshown) from the external steel shell 26.

An opening 21 is provided for charging the `There are several advantagesi y t siagneA f molten` iron and slag. Usually the slag willlbefchargedbefore'the molten iron althoughuthis `is not always critical;LIhe ironwlll bettappedfrom theblast furnacev or othersourceiof supply fthrough a runner `28. zwIn ordertozprevent 'silica and other undesirableimpurities fromrentering `thedesulphurizingladle, a; skimming ladle isprovided. The iront` leaves. the: runnery "and Jentersthe open top ofthe skimming `ladle at4 3U. :.This ladle is provided with adam orskimmer ll. The molten `iron` passes beneath this skimmer andgtheflatingjimpurities arevheldxback at 32.A

Theexitend of theskimmlng ladle' lspro`vlded with'a cover 33 which`redicesaccess ofair to he interior of the treatn'ientladle.v After the.alsomade of carbon refractory or `may be made of so-called sillimaniterefractory or `other high 4aluminous material. Figure 2a showsadifferent length of extension I8'. The impeller'assembLv lisfcax''iedon` the rotatingxshaft 41 whichmay fbemade of asuitameheat resistantmetal with ,a `hollowinterior I8 into which cooling air or v 'other nula1s blown by s. suitable pipen. :The t Anotherform ofimpellercapablejoflifting'pig impeller, extension and shaft z me` desirably threaded woneanother4 at so and u.

iron is shown in Figure 3; In this case the im*- `peuerA headu' isdesirabiyfmade or carbonfrdesulphurizingladleisproperly filled, thesource ofmolten iron is cut off atitherunner. 'I'he iron still remainingintheskimming lad1evispoured into the desulphurizing ladle bytiltingqthe skim-` mer `about the trunnionl 3l. ThereuponV 4theAnlopening 3G is providedin the cover of the ladle for animpeller L31.`impeller is preferably a self-contained unit; having an electric motor3B and speed reducer 39. `The motor `will;preferalznlyfbe avariable'speed `direct current motorproduclng .an impeller speed of 50`to200 revolutions i, `per minute or more. The speed chosen may vary.with' different instal1ations.` Thewimpeller and i its;` operating."mechanism co- `@operate with ythe 'cover 24` to reduce access `;of fairatthis point and may beN removed as VYaiumt l from the desulphurizingivessel and ya "cover 40` g substitutedas shown in Ilgurefla.` .i i i`ladle whose axis-of symmetryis vertical for de-` fsulphurlzlngtpigiron. .L 'Iliisxfmakesl` it possible `to locate thevdesulphurzing slagat. thel level of v in employing a. i

fractory. It isattached to the rotating. mechganism by means of-asillimanite. cyaniteo'r other extension lili 'Ifile carbon`"r.efra'ctory `is mat chined to" provide a spiral fluting y52.`Theginiy i 2o: skimming `ladleancl coverlarellremoved and a.

n suitable permanent `cover I5 is placed on i the adle to cover theopening 21 as shown -in Fig-` Vurela.

:'peller vis mounted that the spiral fluting pref-` erablyextends intothe Die ironand below the slag-metal interface, The rotation ofi thestirrer produces `acorresponding rotary movement in the slag and metalwith which it isin contact. IBy virtue `of the flutin'g,` a verticalmotionr is also produced whichpreferably lifts the iron and the slagabovethe level which it `would V@nxarrnally takeif` the iluting `wereabsent. The `eiect'offthelpumping `lnipller is"to lift `the `upthefsulphur removal.

moltenmetal `from the bath `and bringit into i ,netter contact with thedesulphurizingglagthere@ by exposing fresh slag-metal interfaces tospeed An` alternative apparatus for producingthe required agitation isvshown in -Figures 4 and 5.

This consists lof arotating stir-rer of carbonor t other suitablerefractory which is supported by 4l a sillimanite extension It fasshownA in Figures maximum ladle `crosssec-tioniwith utilizationiof fullladle capa.city.l"Thus the slaggmetal interf` face is of`xnaurixnumareal fora convenient refractoryis'tructure.Refractorywrepairs and replacements are` much easier inni.` ladlewhose paxisof symmetry is vertical than in one whose t axis; of symmetry :ishorizontal.` `In a normal *ladle whose axis ofsymmetryislvertical, a'larger `proportion of i the pigqiron willfbe at` relatively greatldepthin the ladle than'in a ladle whose faxistof symmetry is horizontal.`Q'Zl'herefore t in a ladle 4whose axis of symmetry isgy vertical/theretis'greater importance in securing emcient stirring and stirring whichislleective from the standi `point l of desulphurization.` i Y,Differentwtypes'offim" llers-lmay be to y `irnpartfstlrrlng `primarilyin Aahrizontal plane,

but with an upward stirring"component.` Fig?,`

urepZ shows a pumping.typeotfimpeller of cir-` `culacross sectionmadesuitably oftcarbon re-` p A fractories.4 The jbody of the "impeller`Il "has pumping passages 42 extending diagonallyupiward and `outwardshown; t The numberfof pumpingjpassages `42 isnot critical.vi'1'heeffectv u of the pumpingimpellerfis to lift molten metalenV t from thebath into contact .with the desulphurizing slag. i The inlet 43 Vof thel pumping impeller willwpreferably be located` below the slag-metal tinterface u andthe outlet'lull .above the slagmetalinterfaca asshown.:toicausedistribution f ofymolten metal directly into uthe slag.-The level the impeller 4| isfmadeadjustable"` a's re- 1 quiredby usinganyuone of #several `different i lengths of extensions Extension;l (Il`may be l anua. 'rae-surreale can te made fromm 4round carbonlelectrodeof suitable diameter',` for example l0 inches to 15 inches ormoreifnecessary. The round electrode can be machined to form arectangularV or other section 5I hav-t` ing one or more planesurface 54.For example. arectangle 5 inches wide and 10 inchest l5 `inches or -morein length" might be used.- The stirrer is immersed in the slag andmetal. By'

its rotation a corresponding-rotary motionV of i 1 the contents oftheladleis produced. 1

' )For betterpresults two or-more stirrers Illl and 4i* maybe used asshown in Figures 6 and 7. If two Vstirrers aroused, they should bespacedso that the clearance between therotating carbons should not be toogreat,` as for example. a clearance of approximately 6 inches to 1 8mche l These Surfers mayfrtate in the same Y direction or inoppositedirections. `If they `a`re rotated inthe same direction, theentiremasslof liquid contents of theladle willbe vgiven acorrespondingrotating" 'motion as showny Jbyfthe arrowsinFigurefl. i i f A Where aplurality of stirrers are to beused as in Figures 6 and 7,`improvedresults` are obtained by having thestirrerseflectiveat'different levels in the bath. Thus inFigure 6` theAlstirrer 4i? extends deeper'into the bath than the stirrer I I; thelatter stirrer operating chiefly v*in the 'slag and `not extendng'anygreat. depth below `the`^`slagmetal interface. These twostir``r`ers`-produce a"'rlative movement betweeny the 519g andthemetal andalso between respective Portionsof themetal. i

' In order to speed up the rate oflreactionuit vis i `desirable to' havea relative movementbetween theslaglayer and the metal. `'AIhe naturaltendency would befor the `slas layer` and the metal` :layer to rotatetogether and thefrelativeumotion I.

sirable. Increased relative motion can be obtained by using theapparatus shown in Figures 8 and 9. A darn 55 is immersed in the slaglayer and if desired, below the slag-metal interface 4I. Any desirednumber of dams may be used. The effect of the dam is to impede therotation of the slag Whilst permitting a relatively unhampered rotationof the pig iron, thereby causing relative motion between the pig ironand the slag. The dam may if desired occupy the opening 21 when metal isnotbeing charged, with suitable packings to exclude air.

Where there is considerable variation in the level of the pig iron, itis desirable to make the height of the dam adjustable s that the damwill always extend down to the slag-metal interface and also preferablyslightly below the interface as shown. In Figures 10 and 11 I show arefractory dam 55' suitably of carbon refractory supported on a bracket58 and adjustable as to height by an adjusting screw T threaded throughthe bracket and making thrust bearing connection with the dam 55'. Toprevent the dam from rotating, a guide 5l extends from the darn throughanopening in the bracket 58.

structures of Figures to 12 will be provided with a suitable gas-tightcover as shown in Figure 1.

To further promote better transfer of the impurities from the molteniron to the slag, the apparatus shown in Figures`l3 and 14 can beapplied either alone or in conjunction with the dam 55 and/or the twostirrers 4I and Il* as shown. In this type of apparatus the refractorylining is constructed to form an inclined vane 82 extending around theladle circumference from point 8l near the bottom to point 64 near thetop and providing a vane shelf 65 which is a maximum at 63 and a minimumat 84. The vane 62 is capable. of converting some of the rotary motionof the liquid iron in the ladle into vertical motion, thereby bringingthe metal from the bottom of the ladle upward to establish contact withthe supernatant slag. The rotatory action `of the metal may be impartedby the stirrer; 4I;i and 4|4 or in other suitable ways.

Instead of usi-ng the mechanical agitators for producing o. rotarymotion in the molten pig iron in the ladle, it is also possible toproduce a rotary motion by means of electromagnetic action. By usingpolyphase alternating current to produce rotating magnetic fields in aniron core suitably n placed around the periphery of the ladle,preferably at or below the slag-metal interface, the.

current induced by the alternating electromagnetlc field in the moltenmetal contained in the ladle causes a rotary motion of the metal in theway that rotary motion is produced in a. polyphase induction motor.

Figures and 16 show such a polyphase stir,- ring ladle having a winding66 intended for threephase alternating current, with phase field coils81, 88 and 69 connected to a source at 10, I'I rand 12 and connectedtogether at 13 (Figure 15).

`between the two would not be as great as de- Star connection is shown,but it will Abe evident that any suitable system of connections may beused. 'I'he winding is surrounded by an annular magnetic core 'i4suitably slotted to receive the Winding as at 15 and desirablylaminated. Low frequency alternating current at, for example, 25 to 100cycles will preferably be used.

The device of Figures 15 and 16 will cause simultaneous rotation of boththe slag and the metal. To secure differential movement between the slagand the metal, a slag dam 55 of any de-l sired type will desirably beused as shown in Figure 16; or an inclined vane 62 as also shown in thisfigure; or mechanical stirrers Will be ernployed as shown at H3 and l I4in Figure 16, preferably causing the slag to rotate oppositely from themetal.

Figures 17 and 18 illustrate a variant electromagnetic stirring device.The desulphurizing vessel 20 is surrounded by a polyphase field winding18 of Gramme ring type, wound on an annular magnetic core l1, suitablylaminated, and provided with magnetic poles 18. In the speciflcconstruction, a three-phase winding consists of phase coils 19, 80, and8| connected in delta formation to three-phase lines 82, titly and 84from an alternating current source at commercial frequency. The magneticcore Il and the poles 18 will desirably be assembled from separateunits, fastened together inany suitable manner.

The .Winding 15 and core 'Il are very desirably inclined or canted withrespect to the horizontal as shown in Figure 18, so that in addition toa horizontal rotary or whirling motion in the iron, there will be ahelical upward stirring component due to the inclination of the windingand core.

There will preferably be one coil and one pole for each phase, and, ofcourse, the number of phases in the polyphase system may be varied. Ingeneral, the smaller the number of poles, the

'faster the stirring, other conditions being unsubstantial portion ofthe iron bath and not lmerely through the wall of the ladle. It ispreferable, therefore, to use a small number of poles,

5 for example from two to six poles.

'I'he ladle of Figures 17 and 18 is desirably provided with a slag -darn55 and with impellers H3 While the iron whirls in upward helical paths,the whirling of the slag is retarded by the dam 55. The impellers H3 andH4, which operate in the slag, will desirably rotate the slag oppositelyfrom the rotation of the iron. For example, if the iron rotates in thedirection of the arrow 85, the slag will preferably be rotated by theimpellers in the opposite direction.

It will, of course, beunderstood that in Figures 15 to 18 the ladleswill be provided with air tight closures.

Instead of a moving wave form of electromagnetic stirrer as shown inFigures 15 to 18, a poolsurrounding coreless induction form of any wellknown typemay be used. In Figure l an inductor coil BE' surrounds theupper portion of the metal bath adjacent the slag-metal interface. Theneighboring structural parts of the ladle will desirably be made ofnon-magnetic metals or alloys or non-metallicematerials. A suitablealternating current of low frequency, for example 25 to 100 cycles, willbe connected to the coil 66.

The coil will desirably carry a, high wattless currentdue to resonanceobtained through suitably connected condensers as well known in the art.

v,`will.lso-me m m m dsirab-les isfcompaniedaby considerablewheatiobtained ativrelativelyzhigh Cossa v l i i helinductor` costirringfis un- `The ladlesffor containing: the moltenmetaliand i slagto be rotated as describedabove.` should have atyertical axisofsymmetryabout `whichthe.rotam tion takes place. For example; the interiorrcouldbe2-shaped inthekformfof afxcylinder` orinverted* ,truncated cone.` iThe major` axis ofthe cylinder "OJCOIIIS, the

r cone stands `approximately verticallland''rotaon occursaboutthisfaxis. It uislnotinecessary slag-metal interface as thelmetalfrotates about its natural axis. For example, the ovalcrosssection shownl` in^\.1'figure 419whenrotated by anyof "1 thetmeansdescribed turns about an axis located at the point 85. An element Blofslag-metal in- An illustrative cycle of operations with refer# enceparticularlyto Figure Y1 is;as follows: s The desulphurizing ladle ischarged lthro"u`gh the l i opening `2'lwith the requiredamount of `de-`sulphurizing slag from the poi'l 88. This desulphurizing` slag may, forexamplecompr`ise70 r per `cent of molten blast furnace slagpreviouslywithdrawn from the blast furnace, 20 per cent of l ."bur'ned limeand 10percent fluorspar.` `'I'he blast furnace is tapped andaboutl'tons `ofiron is transferred into `the ladle 1.29. As del scribed above, allsiliceous contaminations should be removed from the `flowing streamioiironby dams or skimming devices. 'I'he desulphurizing ladle and itscharge is then closedagainst free. access of air Vor oxygen to theinterior. `Desul-i` rphurizing is continued usingagitationluntil theproper sulphur content of the iron hasbeen ob-- hat the". crosssectionof theladleon1a"planefat.'A rightiangle to this axis of`syini'netrybe circular. `Indeedfit may ibe-"advantageousto user-someother.V y :shape as `for examplean ellipticalor ovalsection,thereby,facilitatingthelformation of new areas of 5000:'1` or more,` allconditions. if

onA may` berobtained from a `blast! fur- *nacel-productf containing"`initially as much as oaioeawroeoa, smpnuror more. 'rhesmphur lcontentfof lthelslagsmay rise to 5% or 1062.

sulphur or more and al ratio'of sulphur in slag to f sulphur in theironof 5 00:1"o1 1000:"1`fand even `denendingfup'on the chosen Y processesand apparatus `de scribed herein may be used for the removal ofsulphur`frormolten"pigiironsupplied 4by fur- "1* nacesother than* a`blast furnace, as forexample ..a"cupola." `@Theuse forfsuch purposesis"ex` pressly-included' herein.1

` ,tions and modifications to meet individualwhim -1Inview`of theinvention'and disclosurevaria- 'or particular needwill doubtlessbecmeevident fto others skilledin the art, to obtain all or ypart ofthe"benefits ofmy invention without copying the structure shown, and I,therefore, claim all such in soV far as they fall within the reasonable-spirit and scope of my invention.

Havingthus described my invention what claim-as new and desire to securebyLetters Patent is: m'

1. A desulphurizing vessel closed to the at- A`mosphere and providedwitha refractory lining adapted to `hold a charge of molten pig iron` and abody ofmolten desulphurizing slag on the iron,

electromagnetic means to induce electric cur.-

"rent within themetal as a secondary for imparting a generallyhorizontal rotary stirring to the .iron and means for rotating the slagin a direce tionopposite from that of the4 iron.

` 2. A vessel for desulphurizing molten metal whosemajor vessel axis isvertical having a refractory liningrand adapted to contain molten metaland desulphurizing slag on the molten l metal, walls forming a chargingopening, a metal tap opening and a slag tap opening at a different levelfrom the iron tap opening on a side oppotained. For best results vacuummay be ap- .plied to the ladle, as through a vacuum connecftion 89. 'i

` After the desulphurizing-reaction is completed. the slag is removed bytilting the ladle 2.0 `about the axis 90 andallowing the slag tofrun outthe:

opening 8l (suitably closed against air contamination when not,in use)"into theV slag pot 88.v 'Ihereupontheladlel is tilted in the reverse 1direction about the axisziand the` iron is poured through thetea-potspout"93(suitably sealed when not in use) into thetransferladlesgl. An axis is also provided at 92` for` pouringthe ensite tothemetal tap opening. means for closing the openings against aircontamination, means for tilting the vessel about an axis adjoining onetap opening for discharging'from that tap openthat tap opening. i

3. A vessel for desulphurlzing emetal, whose major axis is vertical,havingal refractory 1in# ing to receive molten metal andslag, means forlifting the metal from a level just below the slag and delivering itupon the surface of the slag, and

separate means for stirring the body of the metal. t

m 4, A vessel for desulphurizing metal whose major vessel axis isvertical, having a refractory lining to receive molten metal and slag,means for y circulating this` slag at upperlevel without circulating asubstantial part of the molten metal and "tire ladle content, slag" andiron, in#emergency.v Two or more transfer ladlesifmay be4 used `ifnecessary and the stream of metal `i'roi'n the rcie-g4 smphunzmg ladlecan-be interrupted by tilting i the` ladle 20 vwhilst a new `transferladle is brought into position;v -It isrimportarit thatanydesulphurizing slag remainingin thetdesulphur'- izing ladle be kept fromentering theY transfer `ladies 94. The inclined teapotspout S31iseiTective to preventthis. If further precautions are necessary thesmalltea-potskimmer ladle can be placed just ahead of the transferladies v Withgood agitation and efficient slags. Va. pig

iron containing 0.015% sulphur or 0.010%` sulondary.

separate independent means for circulating the `molten metal at the`samemetal upper level at l which the slag is circulated, one of themeans.. being electromagnetic` and operated by inducing electric currentwithin the molten metal as a sec- 5. A vessel-fordesulphurizing molteniron having a vertical axis and adapted to hold molten iron` and slagnoating upon the molten iron, a mechanical stirrer for the slag when theslag `reaches an upper level of the stirrer, stirring the slagindependently of electromagnetic circulation of the iron andelectromagnetic means for stirring the iron differently from thestirring' of the slag when the slag reaches said level.

G. A vessel for desulphuri'zing molten iron ing and means for tiltingthe vessel about an axis adjoining the other tap opening for pouringfrom i whose major axis is vertical, adapted to contain to stir the slagwithout stirring a substantial part molten iron and slag oating on theiron. a meof the body of the iron when slag is present bechanicalcirculating means vfor circulating lthe tween the levels of the two tapopenings and elecslag without circulating a substantial part of thetromagnetic means i'or stirring the iron sepabody of the iron andelectromagnetic means act- 5 rately from the stirring of the slag,acting by inling by inducing current within the iron as a secduction ofcurrent within the iron as a secondary.

ondary, located below the mechanical means, cir- 8. A vessel fordesulphurizing molten metal culating the body of the iron asdistinguished `whose major axis is vertical, having a refractory fromthe slag when the slag level is that within lining, a mechanicalcirculating device adapted to which the mechanical circulating means isl0 operate in the slag when the slag reaches an upadapted to operate.per level and a pool-surrounding coil located in 7. A vessel fordesulphurizing molten iron havthe upper part of the vessel and below themeing a refractory lining adapted to contain the chanical circulatingdevice, said pool surroundmolten metal and desulphurizing slag on theing coil being adapted to induce electric current molten iron, wallsVforming a charging opening, 15 within the upper part of the molten metalrather an iron tap opening and on the side opposite to than in the slagwhen .the molten metal and slag the iron tap opening, a slag tapvopening, means reach the level at which the mechanical circulatfortilting the vessel about axes adjoining the reing device is effective.

spective tap openings for discharge from these f tap openings,mechanical stirring means adapted go v RUSSELL PEARCE HEUER.

